Heat storage tank

ABSTRACT

A heat storage tank  10  includes a heat a body valve  4  having an inflow side passage  41  and an outflow side passage  42  and fitted into an open portion  11  of the heat storage tank, a center pipe  5  communicating with the outflow side passage and extending substantially vertically inside the tank and a mixing prevention plate  6, 60  for preventing mixing of cold water flowing in and hot water stored, wherein a through-hole  63  penetrating through the center pipe and a large number of flow holes  64  are formed in the mixing prevention plate, and the prevention mixing plate has a diameter D 2  smaller than a diameter D 1  of the open portion  11  of the tank.

TECHNICAL FIELD

This invention relates to a heat storage tank, having a vacuum heat insulating layer, for retaining heat and storing a fluid. More particularly, the present invention relates to a heat storage tank that is mounted to a car and is suitable for retaining heat and storing engine cooling water.

BACKGROUND ART

A cooling system apparatus for promoting warm-up of a water-cooled type internal combustion engine of cars has been proposed that arranges a heat storage tank for retaining heat and storing engine cooling water flowing out from the engine in a cooling water circuit, introduces the high temperature cooling water stored in the heat storage tank into the engine and thus promotes warm-up of the engine. In other words, this cooling system apparatus stores excessive heat generated by the engine during the normal operation of the car in the heat storage tank assembled in the cooling water system and warms the engine and the inside of a passenger compartment at the starting of the car.

As described above, the heat storage tank can effectively utilize excessive heat of the engine and can reduce the fuel consumption during the operation of the car from an overall aspect.

Such a heat storage tank 10 generally includes an inner cylinder tank 1 of a stainless steel constituting a heat storage tank main body and an outer cylinder tank 2 similarly formed of stainless steel. As a space 3 between the inner cylinder tank 1 and the outer cylinder tank 2 is kept substantially at a vacuum, the heat storage tank 10 has a heat insulating structure. The inner cylinder tank 1 and the outer cylinder tank 2 are fixed by welding, etc, at an open portion (11). A body valve 4 having an inflow side passage 41 and an outflow side passage 42 is fitted into this open portion in the prior art as shown in FIG. 5A.

In the heat storage tank 10 according to the prior art, however, a part of cold water taken in short-circuits and is, as such, drained from the outflow side passage 42 even when an attempt is made to drain hot water from the outflow side passage 42 by taking cold water from the inflow side passage 41 in the heat storage tank. Consequently, it has been difficult to effectively take out the accumulated hot water.

To prevent such a short-circuit of the cold water, the heat storage tanks described in Japanese Unexamined Patent Publication Nos. 10-71840 and 2003-80929 were developed. Such tanks are basically the heat storage tank 10 shown in FIG. 5B. In other words, a center pipe 5 connected to an outflow side passage 42 of a valve body 4 and extending vertically inside the heat storage tank 10 and a mixing prevention plate 6 arranged above the body valve 4 and preventing mixing of heat-accumulated hot water and cold water flowing in are disposed inside the heat storage tank 10.

In the heat storage tank of the prior art described above, it has been necessary to weld, in advance, the mixing prevention plate 6 to the inner cylinder tank 1 and then to assemble the body valve 4 and the center pipe 5 to the heat storage tank. In consequence, the productivity and the assembly properties of the heat storage tank drop remarkably.

DISCLOSURE OF THE INVENTION

The present invention has been completed in view of the problems described above and its object is to provide a heat storage tank that can improve the drain efficiency of heat-accumulated hot water and can simultaneously improve the productivity and assembly properties of a heat storage tank.

A heat storage tank according to the invention includes a body valve 4 having an inflow side passage 41 and an outflow side passage 42 and fitted into an open portion 11 of the heat storage tank 10, a center pipe 5 communicating with the outflow side passage 42 and extending substantially vertically inside the tank, and a mixing prevention plate 6, 60 for preventing mixing of the fluid flowing in and the fluid stored, wherein a through-hole 63 penetrating through the center pipe 5 and a large number of flow holes 64 for allowing the passage of the fluid are formed in the mixing prevention plate 6, 60, and the prevention mixing plate 6 is shaped into a diameter D2 smaller than a diameter D1 of the open portion 11. Productivity of the tank can be improved because the tank 10 and the mixing prevention tank 6, 60 are formed independently of one another. Because the diameter D2 of the mixing prevention plate 6, 60 is smaller than the diameter D1 of the tank, the mixing prevention plate 6, 60 can be fitted simultaneously with the body valve 4 from the open portion 11 below the tank 10 and the assembly property can be improved.

In the heat storage tank according to the invention, the mixing prevention plate 6 is constituted by a ring-like upper plate 62 and a cylindrical side plate 61 into a bottomed cylindrical shape. Accordingly, the inflow fluid impinges against the upper plate 62, is then distributed through a large number of flow holes 64 and moves upward inside the tank 10, and the fluid (hot water) stored in the storage portion T can be efficiently drained through the center pipe 5.

In the heat storage tank according to the invention, the center pipe 5, the body valve 4 and the mixing prevention plate 6, 60 are shaped into separate members and each component can be easily produced.

In the heat storage tank according to the invention, the body valve 4 and the mixing prevention plate 6 are formed integrally. In the heat storage tank according to the invention, the center pipe 5 and the mixing prevention plate 6, 60 are formed integrally. In the heat storage tank according to the invention, further, the body valve 4 and the side plate 61 of the mixing prevention pate are formed integrally and the center pipe 5 and the upper plate 62 of the mixing prevention plate are formed integrally. Because the components are integrated by thus taking productivity and assembly factors into consideration, the number of components can be decreased.

The present invention will become more apparent from the following description of preferred embodiments thereof when taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal sectional view of a heat storage tank according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a heat storage tank according to a second embodiment of the present invention.

FIG. 3 is a longitudinal sectional view of a heat storage tank according to a third embodiment of the present invention.

FIGS. 4A and 4B show two modified examples of the third embodiment.

FIGS. 5A and 5B are views for explaining two heat storage tanks according to the prior art.

BEST MODE FOR CARRYING OUT THE INVENTION

Heat storage tanks according to embodiments of the invention will be hereinafter explained with reference to the drawings. FIG. 1 is a longitudinal sectional view according to the first embodiment of the invention. The heat storage tank according to this embodiment is provided in an engine cooling water system of a car, accumulates excessive heat of an engine and is used for warming the engine and inside of a passenger compartment at the starting of the car.

A heat storage tank 10 includes a inner cylinder tank 1 made of a material having high corrosion resistance (such as SUS304 stainless steel) and an outer cylinder tank 2 made of a material having a predetermined mechanical strength (such as SUS304 stainless steel). A space 3 between the inner cylinder tank 1 and the outer cylinder tank 2 is substantially kept at a vacuum to provide a heat insulating structure. The inside of the heat storage tank 10 is a storage portion T of the fluid. This tank 10 is mounted substantially vertically to the car in such a fashion that its bottom faces upward and its open portion 11 faces downward. In consequence, the open portion 11 of the heat storage tank 10 is positioned below the storage portion T in the direction of gravity. The inner cylinder tank 1 and the outer cylinder tank 2 are fixed to each other by welding or like means in the proximity 12 of the open portion 11.

A body valve 4 formed of a material having small heat conductivity such as a resin (Teflon, a trade mark, for example) is fixed fluid-tight to the open portion 11 of the heat storage tank 10 by means such as screwing or bonding. An inflow side passage 41 through which engine cooling water flows and an outflow side passage 42 through which engine cooling water (hot water) stored in the storage portion T flows out are formed inside the body valve 4. Incidentally, the outflow side passage 42 is open into the tank at substantially the axial center position whereas the inflow side passage 41 is open into the tank at a position deviated from the axial center. These inflow and outflow passages 41 and 42 are connected to inlet/outlet pipes of the engine cooling water system, not shown, respectively.

In this embodiment, a mixing prevention plate 6 is fitted to an upper surface 4 a of the body valve 4. The mixing prevention plate 6 has a bottomed cylindrical or cup-like shape that is formed as a ring-like upper plate 62 having a through-hole 63 for the passage of a later-appearing center pipe 5 and a cylindrical side plate 61 are formed integrally with each other. The mixing prevention plate 6 is fixed to the upper surface 4 a of the body valve 4 with its open side facing downward. A large number of flow holes 64 through which engine cooling water entering the tank 10 passes are bored in each of the upper plate 62 and the side plate 61. In this case, the flow holes 64 need not be formed in the upper plate 62. Furthermore, the mixing prevention plate 6 is formed into a diameter (outer diameter) D2 that is smaller than the diameter D1 of the open portion 11 of the tank 10.

One of the ends of the center pipe 5 for guiding drainage of engine cooling water (hot water) stored inside the heat storage tank 10 is connected to the outflow side passage 42 of the body valve 4, passes through the through-hole 63 of the mixing prevention plate 6 and extends substantially vertically at the center of the tank 10. The other end of the center pipe 5 is open to the storage portion T near the bottom face of the tank.

In this embodiment, the body valve 4, the center pipe 5 and the mixing prevention plate 6 are formed into separate members.

In the embodiment having the construction described above, productivity of the tank becomes high because the tank 10 and the mixing prevention plate 6 are independent. Because the mixing prevention plate 6 is formed to an outer diameter D2 smaller than the diameter D1 of the open portion 11 of the tank 10, the mixing prevention plate 6 can be inserted easily, and simultaneously with the body valve 4, from the opening portion 11, and the assembly properties can be drastically improved.

In the embodiment having the construction described above, engine cooling water flowing into the tank 10 through the inflow side passage 41 of the valve body 4 moves upward, impinges against the mixing prevention plate 6 (upper plate 62), is distributed through a large number of flow holes 64, moves further upward, enters the center pipe 5 from the upper opening of the center pipe 5 and is discharged as a downward flow. A series of flows serially guides hot water (engine cooling water) heat of which is accumulated in the storage portion T of the heat storage tank 10 into the center pipe 5. Accordingly, engine cooling water (cold water) flowing into the tank 10 is not short-circuited and drained, and hot water can be efficiently drained. The mixing prevention plate 6 by itself suppresses stirring and compulsive convection of engine cooling water (hot water) inside the tank 10 by the jet stream blown from the inflow side passage 41 into the tank 10, and prevents mixing of hot water and cold water inside the tank 10.

FIG. 2 is a longitudinal sectional view of a heat storage tank according to the second embodiment. The second embodiment is different from the first embodiment in the structure of the mixing prevention plate 6. In other words, the mixing prevention plate 6 according to the second embodiment is constituted as a whole by only a ring-like plate 60. A through-hole 63 for the passage of a center pipe 5 is formed at the center of this ring-like plate 60 and a large number of flow holes 64 are formed around this through-hole 63. The ring-like plate 60 as the mixing prevention plate 6 is arranged somewhat above the upper surface 4 a of the body valve 4 and is fixed to the center pipe 5. The outer diameter D2 of the ring-like plate 60 as the mixing prevention plate 6 is smaller than the diameter D1 of an open portion 11 of the tank 10. In this case, the plate 60 and the center pipe 5 may be formed integrally with or separately from each other. The rest of the constructions are the same and an explanation will be omitted.

In this second embodiment, the same function and effect as that of the first embodiment can be obtained.

FIG. 3 is a longitudinal sectional view of a heat storage tank according to the third embodiment. In the first embodiment, the body valve 4, the center pipe 5 and the mixing prevention plate 6 are shaped as the separate members but in the third embodiment, the body valve 4 and the mixing prevention plate 6 are formed integrally by molding, and only the center pipe 5 is the separate component. The rest of the constructions are the same as in the first embodiment.

In addition to the function and effect of the first embodiment, the third embodiment provides the effect that the number of components can be decreased.

FIGS. 4A and 4B show two modified embodiments of the third embodiment. In the modified embodiment shown in FIG. 4A, the upper plate 62 of the ring-like prevention mixing plate 6 is formed integrally with the center pipe 5 by molding and the cylindrical side plate 61 of the mixing prevention plate 6 is integrated with the body valve 4 by molding.

In the modified embodiment shown in FIG. 4B, the bottomed, cylindrical mixing prevention plate 6 including the upper plate 62 and the side plate 61 is integrated with the center pipe 5 by molding and the body valve 4 is the separate component.

In the third embodiment and the two modified embodiments, the mixing prevention plate 6 is shaped to a diameter (outer diameter) D2 smaller than the diameter D1 of the open portion 11 of the tank 10 in the same way as in the first embodiment.

Although the invention has thus been described in detail on the basis of the specific embodiments thereof, those skilled in the art could make various changes and modifications thereto without departing from the scope and spirit of the appended claims. 

1. A heat storage tank having a heat insulating structure equipped with a storage portion (T) for storing therein a fluid while retaining its heat, comprising: a body valve having an inflow side passage for causing the fluid to flow into said heat storage tank and an outflow side passage for causing the fluid stored in said heat storage tank to flow outside, and fitted into an open portion of said heat storage tank positioned below the storage portion in the direction of gravity; a center pipe communicating with said outflow side passage and extending substantially vertically inside said storage portion; and a mixing prevention plate arranged inside said heat storage tank, for preventing mixing of the fluid flowing in and the fluid stored; wherein a through-hole penetrating through said center pipe and a large number of flow holes for allowing the passage of the inflowing fluid are formed in said mixing prevention plate, and said prevention mixing plate is shaped into a diameter D2 smaller than a diameter D1 of said open portion.
 2. A heat storage tank according to claim 1, wherein said mixing prevention plate is shaped into a bottomed cylindrical shape having a ring-like upper plate and a cylindrical side plate.
 3. A heat storage tank according to claim 1, wherein said center pipe, said body valve and said mixing prevention plate are shaped into separate members.
 4. A heat storage tank according to claim 2, wherein said body valve and said mixing prevention plate are shaped integrally with each other.
 5. A heat storage tank according to claim 1, wherein said center pipe and said mixing prevention plate are shaped integrally with each other.
 6. A heat storage tank according to claim 2, wherein said body valve and said side plate of said mixing prevention plate are integral with each other and said center pipe and said upper plate of said mixing prevention plate are integral with each other. 